Author: Oliver Roese
Date: 05:36:24 06/13/00
Go up one level in this thread
On June 12, 2000 at 05:46:59, Rémi Coulom wrote: >On June 10, 2000 at 13:44:35, blass uri wrote: > >>On June 10, 2000 at 11:54:17, Ed Schröder wrote: >> >[...] >>> >>>Maybe the opposite is true. It depends per program how the programmer >>>looks at things. For this position I would say that having 2 outside >>>passers usually is a great advantage and as such is rewarded by a chess >>>program. If so then this position is an exception to the rule. And the >>>end-game is full of exceptions much more than the mid-game. >>> >>>Ed >> >>Having 2 outsides passed pawns is an advantage but having 2 advanced passed pawn >>is also an advantage. >> >>The problem is to know which advantage is bigger. >> >>I agree that it is not a simple problem and I understand the fact that >>programmers prefer to waste more time about other problems. >> >>I still believe that it is possible to see it at evaluation time by an array >>64*64*64 of distance to promotion. > >You are perfectly right about this idea. I do it in TCB. I have a table for >distance to promotion for KPK and PPK. In fact, it is not really a table of >distance to promotion, but a table that gives the maximum number of "not a King >move by the opponent" before the pawn is promoted. I call it "extended square of >the King". It is not in the latest version of TCB. I will make it available in >the next version. If programmers are interested in the code to generate the >table, I will send it to them. > >PPK is nice, but KPK is probably much more useful. TCB can solve WAC #100 in 25 >seconds or so on a celeron 400 thanks to it. It saves 3 or 4 plies as compared >to the standard "square of the Pawn" rule (or is it "square of the King"?). It >is also very good at detecting that a pawn can win a tempo by checking the >opponent on its way to promotion. > >I do not think it would solve this position though. I am not a good chess >player, but the position after the Queen exchange seems unclear to me. Black can >promote first, but White will promote on the next half move. Is it a winning >advantage? Or I might be missing something. I will try it on TCB when I am back >home. > >Greetings, >Remi Here is a human-like approach: Apply the rule of the "wandering square". I got it from Awerbachs book about pawnendings: [D]8/8/1k6/8/P2P4/8/8/K7 w - - 0 1 In the above diagram the two white pawns are on the corners of a square (a4-d4-a7-d7). The rule say, that the two pawns are unstoppable by the opposite king, if their common square has reached the edge of the board. Since this is not the case, here black has hope to stop the pawns. (He will hold the draw with 1..Ka5). [D]Q3q3/4k3/8/5p2/2p5/8/P6P/4K3 w - - 0 1 This position is from blass uri. According to the rule the white pawns are unstoppable. But the blacks pawns are unstoppable to, after the unavoidable ...f4. Since we have no dumb advice here, a search is required. It reveals, that black wins after 1.Qxe8+ but he is only up a tempo. Oliver Roese
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